Structure for and method of cooling granular material



June 113, 167

H. W. DIETERT 3,324,566

STRUCTURE FOR AND METHOD OF COOLING GRANULAR MATERIAL Filed Oct. 4, 1965 4 sheewsheet 1 SIGNAL SENSING AND J MOTOR CONTROL UNIT AL N ING AND MOTOR CONTROL 90 I08 I CONTROL 1 r V CRCUIT INVENTOR. 96 HARRY DIETERT ATTORNEYS June I3, 1967 H. W. DIETERT 3,3245%6 STRUCTURE FOR AND METHOD OF COOLING GRANULIIR MATERIAL Filed Oct. 4, 1965 SIGNAL SENSING AND MOTOR CONTROL 4 SheetsSheet 2 ISO 2IO I96 2I2 SIGNAL SENSING AND MOTOR CONTROL 2w m 230 I TIMER k 206\ I I I I I l I II I I i f I I INVENTOR. HARRY W. DIETERT ATTORNEYS Filed Oct. 4, 1965 June 13, 11%? H. w. DIETERT 3,32 5

STRUCTURE FOR AND METHOD OF COOLING GRANULAR MATERIAL 4 Sheets+Sheet$ 236 2& 238- 246 MW. AL SENSING AND MOTOR CONTR TIMER SIGNAL SENSING AND MOTOR CONTROL UNIT INVENTOR. HARRY W. DIETERT ATTORNEYS June H3, 1%? H. w. DIETERT 3,324,566

STRUCTURE FOR AND METHOD OF COOLING GRANULAR MATERIAL Filed Oct. 4, 1965 4 Sheets-Sheet 4 IGNAL 0 AND MOTOR CONTROL INVENTOR. HARRY w. DIETERT BY 40%V-ZZZWQQ ATTORNEYS 3,324,566 STRUCTURE FUR AND METHGD F COOLING GRANULAR MATERIAL Harry W. Dietert, Kerrville, Tern, assignor to Harry W. Dietert Co., Detroit, Mich, a corporation of Michigan Filed Oct. 4, 1965, Ser. No. 492,375 14 Claims. (Cl. 3420) The invention relates to granular material conditioning apparatus and refers more specifically to a structure for and method of cooling granular material prior to the conditioning thereof as by a moldability controller.

In foundry operation it is necessary to control the mold ability of granular material such as foundry sand. The foundry sand is returned from a foundry operation in variable temperature and moisture conditions and must be reconditioned before being reused. To obtain the speed required in conditioning the foundry sand it is desirable to place the sand in a conditioning mill under the control of a moldability controller such as disclosed in the United States patents, No. 3,136,009 and No. 3,- 136,010 at a predetermined maximum temperature. Thus it is necessary to cool foundry sand before it is placed in a mixer for reconditioning.

In the past it has been the practice to cool foundry sand or similar granular material through the use of a constant flow of air therethrough in conjunction with a variable amount of Water added thereto. The water in the past has been varied in accordance with the temperature of the granular material to be cooled. In some prior installations the cooling water has been further regulated in accordance with the moisture in the granular material to be cooled.

It is not economical or eflicient to cool material such as foundry sand with a constant flow of cooling air. More air is required for efficient cooling at higher sand temperatures of for example 450 F. than is required when the temperature of the sand to be cooled is lower as for example 150 F. The constant flow of air which may not be needed in accordance with the temperature of the granular material is wasteful of power required to move the air. It also wastes fine material blown out of the foundry sand which may be for example an additive such as wood flour or sea coal bonding agent which is lost and must be replaced in the subsequent conditioning of the granular material. Also in the winter the air which is blown is usually plant air which has been heated and excessive blown air which is usually directed out of the plant adds to plant fuel cost.

It is therefore one of the objects of the present invention to provide improved structure for cooling granular material.

Another object of the invention is to provide an improved method of cooling granular material.

Another object is to provide structure for cooling granular material including means for blowing a quantity of air through the granular material in accordance with the value of at least one parameter of the granular material and means for adding a quantity of Water to the granular material in an amount regulated by the quantity of air blown through the granular material.

Another object is to provide structure for cooling granular material as set forth above wherein the parameters are the temperature and moisture content of the granular material.

Anothe object is to provide structure for cooling ganular material as set forth above and further including means for controlling the quantity of air passed through the granular material by regulating the rate of flow of the air.

Another object is to provide structure for cooling gran- Patented June 13, 1967 ular material as set forth above and further including means for controlling the quantity of cooling water added to the granular material by regulating the rate of flow of the cooling water.

Another object is to provide structure for cooling granular material as set forth above and further including means for controlling the quantity of air and water passed through and into the granular material by regulating the time of flow thereof.

Another object is to provide structure for cooling granular material as set forth above and further including means for adding the cooling water to the granular material all at once.

Another object is to provide structure for cooling granular material as set forth above and further including means for adding the cooling water to the granular material gradually as the air is blown through the granular material.

Another object is to provide structure as set forth above for cooling a continuous sample of granular material.

Another object is to provide structure as set forth above for cooling separate batches of granular material.

Another object is to provide a method of cooling granular material comprising sensing at least one parameter of the granular material, passing a quantity of air through the granular material in accordance with the sensed parameter thereof and providing cooling water for the granular material in accordance with the quantity of air passed therethrough.

Another object is to provide a method of cooling granular material as set forth above wherein the granular material is cooled in a continuous granular material cooling operation.

Another object is to provide a method of cooling granular material as set forth above wherein the granular material is cooled in a batch type operation in a separate cooling mill.

Another object is to provide a method of cooling granular material as set forth above wherein the granular material cooling is accomplished in a mill used subsequently for conditioning of the granular material in accordance with the moldability thereof.

Another object is to provide a structure for and method of cooling granular material which is simple, economical and efiicient.

Other objects and features of the invention will become apparent as the description proceeds especially when taken in conjunction with the accompanying drawings illustrating a preferred embodiment of the invention, wherein:

FIGURE 1 is a diagrammatic representation of structure for cooling granular material in a continuous operation in accordance with the method of the invention.

FIGURE 2 is a diagrammatic representation of structure for conditioning granular material including structure for cooling the granular material in a batch type operation in accordance with the method of the invention.

FIGURE 3 is a diagrammatic representation of structure for conditioning granular material including cooling structure similar to that illustrated in FIGURE 2 wherein the water is supplied to the cooling mill in a batch type operation rather than continuously as with the structure illustrated in FIGURE 2.

FIGURE 4 is a diagrammatic illustration of granular material conditioning apparatus including cooling structure similar to that illustrated in FIGURE 2 wherein the cooling air and water are supplied for a variable time at a fixed rate rather than for a fixed time at a variable rate.

FIGURE 5 is a diagrammatic representation of granular material cooling structure similar to that illustrated in FIGURE 4 wherein the cooling and subsequent conditioning of the granular material is done in a single mill and the water is supplied in accordance with the pressure of the air supplied.

FIGURE 6 is a diagrammatic representation of granular material cooling structure similar to that illustrated in FIGURE wherein the operation of the blower motor and the delivery of cooling water is in accordance with time determined by the initial temperature and moisture content of the granular material.

FIGURE 7 is a diagrammatic representation of granular material cooling structure similar to that illustrated in FIGURE 6 wherein the time of operation of the blower motor is determined in accordance with the temperature and moisture content of the granular material the blower motor at a variable ratio.

With particular reference to the figures of the drawings one embodiment of the present invention will now be considered in detail. The granular material cooling structure 10 illustrated in FIGURE 1 includes a continuous conveyor belt 12 along with foundry sand 14 to be cooled is carried to the vibrator 16 over which it is passed to moldability conditioning apparatus not shown.

A horizontal screen 18 is provided in the vibrator 16 which is porous to cooling air blown up through the screen 18 but which is impermeable to the granular material passing thereover. The structure 20 for blowing air into the vibrator 16 includes a blower 22 and the drive motor 24 therefor. The blower 22 is connected to the air duct 26 for delivery of air thereto in accordance with the operation of the motor 24 and the position of the throttling vane 28 therein. The duct 26 is conneoted to the vibrator 16 by the flexible section 30 which permits independent vibration of the vibrator 16.

Water is supplied to the granular material 14 on the continuous conveyor 12 through the water pipe 32 and the spray head 34. Water is supplied to the pipe 32 at a pressure set by the pressure regulator 35 in accordance with the opening of the throttling valve 36. The throttling vane 28 and the throttling valve 36 are controlled in accordance with sensed parameters or physical characteristics such as temperature and moisture of the granular material 14 traveling on the conveyor 12 in response to the signal sensing and motor control structure 38.

The structure 38 as illustrated in FIGURE 1 includes a thermocouple 40 extending into the granular material 14 on the conveyor 12 which is mounted on the pivot mounting 42 and held in the granular material 14 by means of the weight 44 for sensing the temperature of the granular material 14 and providing an electrical signal proportional thereto over the conductors 46 to the signal sensing and motor control unit 48. A moisture probe 50 also mounted on a pivot mounting 52 and held in the granular material 14 by the weight 54 which may be similar to the moisture probe illustrated in Uni-ted States Patent No. 3,141,129 provides an electric signal over the conductors 56 to the signal sensing and motor control unit 48 proportional to the moisture content of the granular material 14.

The signal sensing and motor control unit 48 may be similar to the structure illustrated in United States Patent No. 3,000,064 and is constructed to provide an output control signal on the conductors 58 which is directly proportional to the temperature of the granular material 14 and inversely proportional to the moisture content of the granular material 14. The exact details of the signal sensing and motor control unit 48 are not given since they may be provided by the ordinary mechanic in electric controls.

The signal sensing and motor control structure 38 is connected to the electric mot-or 60 which drives pinion 62 engaged with rack 64. Rack 64 in turn is pivoted at 66 to the lever 68 fixed to the throttling vane 28 centrally thereof for rotation thereof. The lever 68 is pivoted at 70 to the link 72 which is pivoted by pivot means 74 at the opposite end thereof to one end of the lever 76 which is pivotally mounted centrally by pivot means 78. The other end of the lever 76 is pivotally connected by pivot means 80 to the adjusting link 82 operable on reciprocable movement to adjust the throttling valve 36.

Thus in operation of the continuous granular material cooling structure 10 illustrated in FIGURE 1 the conveyor belt 12 will be moving constantly in the direction of arrow 84 about the pulley 86 to deposit the granular material 14 on the vibrator 16. The vibrator 16 is vibrated to move the granular material 14 over the screen 18 in the direction of arrow 88. As the granular material 14 moves along the conveyor 12 the temperature thereof is sensed by the thermocouple 40 and the moisture content thereof is sensed by the moisture probe 50, the electric signals from the thermocouple 40 and the mo sture probe 50 are passed to the signal sensing and motor control unit 48 where they are combined to provide a single output signal operable to drive the motor 60 in a direction and magnitude depending on the temperature and moisture of the granular material 14. The higher the temperature of the granular material the further the motor 60 will be driven in a direction to open the throttling vane 28 and the throttling valve 36. The greater the moisture content of the granular material 14 the less the motor 60 will be driven in the direction to open the throttling vane 28 and the throttling valve 36.

On rotation of the motor 60 in a direction to open the throttling vane 28 and throttling valve 36 the pinion 62 will be rotated to move the rack 64 in for example an up direction to pivot the lever 68 about the center thereof and open the throttling vane 28. The right end of the lever 68 is thus caused to move down in FIGURE 1 so that the link 72 moves down and because of the connection of the lever 76 therewith and the central pivot mounting 78 thereof the link 82 is caused to move up thus opening the throttling valve 36 in proportion to the opening of the throttling vane 28.

Air is thus permitted to proceed down the conduit 26 under pressure of the fan 22 driven by the motor 24 to the flexible section 30 of the conduit 26 and up through the granular material 14 on the vibrator 16 to cool the granular material. The water proceeds at a pressure set by pressure regulator 35 through the throttling valve 36, pipe 32 and out through spray head 34 onto the granular material 14 on conveyor 12 to aid in cooling the granular material.

Thus in accordance with the granular material cooling structure illustrated in FIGURE 1 granular material is continuously cooled by an amount of air determined by the parameters or physical characteristics, that is temperature and moisture content, of the granular material moving on the conveyor 12. The quantity of water added to the granular material is determined by and proportional to the quantity of air passed through the granular material and both the air and water are provided in a continuous operation.

It will be understood that while a finer control of the temperature out of the granular material cooling structure 10 may be obtained using the moisture probe as well as the thermocouple that the use of the moisture probe 50 is not essential to the operation of the granular material cooling structure 10 which is primarily intended to provide a granular material output having a specific temperature through application of a quantity of air therethrough determined primarily in accordance with the initial temperature of the granular material.

The granular material conditioning apparatus illustrated in FIGURE 2, includes the cooling structure 90 which provides for cooling batches of granular material in a separate cooling mill 92 for subsequent depositing in the mill 94 in which the granular material is conditioned in accordance with the moldability thereof as determined by the moldability controller 96 which may be, for example similar to the moldability controller disclosed in United States Patents No. 3,136,009 and No. 3,136,010 referenced above. The moldability controller 96 controls moisture passed to the mill 94 through the pipe 98 by means of the solenoid operated coarse and fine solenoid operated water control Valves 100 and 102, respectively.

The granular material cooling structure 10, besides mill 92, includes the thermostats 104 and moisture probe 106 positioned in the batch hopper 108 which receives a batch charge of granular material and additives from the storage bin 110. The blower 112, drive motor 114 therefor and duct 116 are provided in the granular material cooling structure 90 for delivering air into the mill 92 in accordance with the position of the throttling vane 118 pivotally mounted in the duct 116. Water is sprayed into the duct 116 through the spray nozzles 120 connected to pipe 122 including the pressure regulator 124 and throttling valve 126 therein.

In operation a signal sensing and motor control unit 128, such as unit 48, receives the electrical signal from the thermocouples 104 and the moisture probe 106 to drive the motor 130 in accordance therewith. A pinion 132 is connected to the motor 130 and drives the rack 134 vertically to pivot the centrally pivoted lever 136 about the central pivot mounting thereof to angularly adjust the vane 118 connected thereto. The link 138 simultaneously is moved vertically to similarly adjust the valve 126 in the water line 122.

Thus, again it will be seen that the quantity or amount of air passed through the batch of granular material in the mill 92 will depend on the temperature of the batch of granular material in the batch hopper 108 to be cooled and the moisture content thereof. The amount of water is then determined in accordance with the amount of air provided to the mill 92.

The water can of course be sprayed over the top of the granular material in the mill through a spray head 140 connected to the pipe 122 or may be forced upward through the entry pipe 142 again connected to the pipe 122 in place of spraying the, water in the duct 116 through the spray nozzles 122.

In the modified batch type granular material cooling structure 144 illustrated in FIGURE 3 the bin 146, batch hopper 148, cooling mill 150 and granular material conditioning mill 152 are the same as the corresponding elements in the granular material conditioning apparatus of FIGURE 2. Similarly the thermocouples 154, moisture probe 156, signal sensing and motor control unit 158, fan 160, fan motor 162, control motor 164, pinion 166, rack 168, throttling vane 170, lever 172 and link 174 are the same as the similar members of granular material cooling structure 90, illustrated in FIGURE 1.

In the granular material cooling structure 144, illustrated in FIGURE 3, the water is fed to the cooling mill 150 through the pipe 178 at the top of the mill 150 from the Water tank 180. The amount of water passed into the mill 150 is determined by balancing the bridge circuit 182 by the capacitor 184. The capacitor 184 is adjusted .on vertical movement of the linkage 174 to determine the required amount of water in tank 180. The water is allowed to pass through solenoid operated valve 186 and pipe 188 into the tank 180 until the capacitance between a member 190 extending axially of the tank 180 and insulated therefrom and the externor of the tank 180 is equal to the capacitance of the capacitor 184 adjusted by the lever 172 the position of which is determined by the thermocouple 154 and moisture probe 156.

On balancing of the bridge circuit 182 the solenoid operated valve 186 is shut off. The solenoid operated valve 192 connected in the air conduit 194 is then opened so that the air from conduit 194 empties the tank 180 into the mill 150.

In this modification it will be noted that the ultimate quantity of the water passed into the mill from the tank 180 is again determined in accordance with the setting of the vane and therefore the air passed through the granular material in the mill 150 in a predetermined time determined by the timing sequence in the over-all sequencing circuit for the granular material conditioning apparatus of which the granular material cooling structure 144 is a part.

In the modified batch type conditioning apparatus including cooling structure 196 shown in FIGURE 4, the storage bin 198, batch hopper 200, thermocouples 202, moisture probe 204, cooling mill 206, mixer 208, signal sensing and motor control unit 210, control motor 212, pinion 214, rack 216, blower 218, motor 220, air duct 222, water pressure regulator 224, solenoid operated valve 226 and water spray nozzles 228 are the same as the similar elements in the cooling structures 90 and 144.

In the modified cooling structure 196, illustrated in FIGURE 4, the rack 216 engages a timer pinion 230 to adjust the timer 232 in accordance with the temperature and moisture of the batch of granular material sensed in the batch hopper 200. Then during the cycle of the over-all granular material conditioning apparatus (not shown) the timer is energized for a period determined by the setting thereof to open the damper 234 and the solenoid operated valve 226 whereby an amount of air and water are fed to the mill 206 in accordance with the sensed temperature and moisture content of the batch of granular material in the batch hopper 200. In this modification the time of air delivery is controlled in accordance with the sensed parameters rather than the rate of air delivery.

Again in the modified batch type granular material cooling structure, illustrated in FIGURE 5, the storage bin 238, batch hopper 240, thermocouples 242, moisture probe 244, signal sensing and motor control unit 246, control motor 248, rack 250, timer 252, solenoid operated throttling vane 254, fan 256, fan motor 258, air duct 260, water pressure regulator 262, solenoid operated valve 264, water pipe 266 and spray nozzles 268 are the same as the similar elements in the granular material cooling structure 196.

However, in the granular material cooling structure 236, the mill 270 is both a cooling and a mixing mill which may be used in conjunction with moldability control apparatus, such as that illustrated in FIGURE 2, to condition the granular material in accordance with the moldability thereof after the granular material is cooled. The cycle for the mill 270 must of course necessarily be longer since the cooling and conditioning in accordance with moldability take place in spaced apart timed relation.

Also, the solenoid operated water valve 246 in the granular material cooling structure 236 is actuated in accordance with a pressure switch 272 connected to the air duct 260. Thus, when the throttling fan 254 opens the air pressure in the duct 260 to the left, the throttling vane 254 will cause actuation of the pressure switch 272 and subsequent energization of the solenoid operated water throttling valve 262 so that again the water is added to the air in accordance with the quantity of air passed through the granular material as set by the timer 252. The modified granular material cooling structure 274 illustrated in FIGURE 6 includes the storage bin 276, batch hopper 278, thermocouples 280, moisture sensing probe 282, signal sensing and motor control unit 284, control motor 286, pinion 288, rack 290, pinion 292, timer 294, mill 296, fan 298, fan motor 300, air duct 302, water pressure regulator 304, water pipe 306, solenoid actuated water throttling valve 308 and water spray head 310 similar to the similar elements in the granular material cooling structure 2316.

In the granular material cooling structure 274, however, the cooling cycle is initiated by actuation of the solenoid actuated switch 312 which may be actuated by the master control circuit of the over-all granular material conditioning apparatus (not shown) and which completes a circuit from the source of electrical power 314 through the solenoid operated valve 308 and fan motor 300 as long as the solenoid operated switch 316 is energized. The switch 316 is connected to be energized for a time depending on the setting of the timer 294, the operation of which again may be initiated by the overall sequencing circuit of the granular material conditioning apparatus.

The modified granular material cooling structure 318 illustrated in FIGURE 7 includes the storage bin 319, batch hopper 320, thermocouples 322, signal sensing and motor control unit 324, moisture sensing apparatus 326, mill 328, fan 330, fan motor 332, air duct 334, control motor 336, pinion 338, rack 340, pinion 342 and time! 344 similar to the same members illustrated in FIGURE 6.

In the granular material structure 318, however, the fan motor 332 is energized from the source of electric energy 346 through the solenoid operated switch 348 in accordance with the time set on the timer 344 on actuation of the control motor 336. The water pump 350 is operated while the motor 332 is energized through the belt connections 352 and 354 between the motor 332 and a gear ratio unit 356 and the gear ratio unit 356 and water pump 350, respectively. The water is pumped by the pump 350 through the water conduit 358.

While one embodiment of the present invention and several modifications thereof are disclosed in detail, it will be understood that other modifications and embodiments thereof are contemplated by the inventor. It is the intention to include all such modifications and embodiments as are defined by the appended claims within the scope of the invention.

What I claim as my invention is:

1. Apparatus for cooling granular material comprising means for sensing the temperature of the granular material, means responsive to the means for sensing the temperature for blowing a quantity of air through the granular material in accordance with the temperature thereof, and means responsive to the quantity of air blown through the granular material for adding a quantity of cooling water to the granular material in accordance with the quantity of air blown therethrough.

2. Apparatus for cooling granular material comprising means for sensing the moisture content of the granular material, means responsive to the means for sensing the moisture content for blowing a quantity of air through the granular material in accordance with the moisture content thereof, and means responsive to the quantity of air blown through the granular material for adding a quantity of cooling water to the granular material in accordance with the quantity of air blown therethrough.

3. Apparatus for cooling granular material comprising means for sensing the temperature and moisture content of the granular material, means responsive to the means for sensing the temperature and moisture content for blowing a quantity of air through the granular material in accordance with the temperature and moisture content thereof, and means responsive to the quantity of air blown through the granular material for adding a quantity of cooling water to the granular material in accordance with the quantity of air blown therethrough.

4. Apparatus as set forth in claim 3 wherein the means for blowing air includes means for varying the quantity of air blown in a fixed time in accordance with the sensed temperature and moisture content.

5. Apparatus as set forth in claim 3 wherein the means for adding water includes means for adding the water to the air before the air is blown through the granular material.

6. Apparatus as set forth in claim 3 wherein the means for blowing air and adding water include means for blowing the air and adding the water at a fixed rate for a variable time in accordance with the temperature and moisture content.

7. Apparatus as set forth in claim 6 wherein the means for adding water further includes means for adding the water to the air before the air is blown through the granular material.

8. A method of cooling granular material comprising sensing the temperature of the granular material, blowing air through the granular material in a quantity in accordance with the sensed temperature of the granular material, and providing cooling water in the granular material in response to and in accordance with the quantity of air blown therethrough.

9. A method of cooling granular material comprising sensing the moisture content of the granular material, blowing air through the granular material in a quantity in accordance with the sensed moisture content of the granular material, and providing cooling water in the granular material in response to and in accordance with the quantity of air blown therethrough.

10. A method of cooling granular material comprising sensing the temperature and moisture content of the granular material, blowing air through the granular material in a quantity in accordance with the sensed temperature and moisture content of the granular material, and providing cooling water in the granular material in response to and in accordance with the quantity of air blown therethrough.

11. Structure for cooling granular material comprising a conveyor belt along which granular material to be cooled in continually passed, a temperature sensing probe and a moisture sensing probe inserted in the granular material on the conveyor, a signal sensing and motor control unit connected to the temperature and moisture sensing probes for developing a motor control signal in accordance with the temperature and moisture of the granular material passing along the conveyor belt, a trough positioned to receive the granular material from the conveyor belt down-stream of the conveyor belt from the temperature and moisture sensing probes having an air peremable bottom partition therein and including a plenum chamber beneath the air permeable partition through which air may be blown through the granular material as it passes through the trough, means for passing the granular material through the trough, an air blower, an air conduit for conducting air blown by the air blower to the plenum chamber connected at one end to the air blower and at the other end to the plenum chamber, an air control valve in the air conduit, a mechanical linkage for controlling the air valve in the air conduit, motor means connected to the linkage for adjusting the air control valve in accordance with the motor control signal, a water conduit having a pressure regulating valve and a volume control valve in series with each other therein terminating in a sprinkler over the granular material on the conveyor down-stream of the temperature and moisture sensing probes, and a mechanical linkage connected between and responsive to movement of the mechanical linkage for controlling the air valve connected to the volume control valve in the water conduit for regulating the volume control valve in accordance with the position of the air valve.

12. Structure for cooling granular material comprising a granular material cooling mill, a batch hopper for receiving a batch of granular material to be cooled for placement in the mill, means for sensing the temperature and moisture of the granular material in the batch hopper, a signal sensing and motor control unit connected to the moisture and temperature sensing means for developing an electric signal in accordance with the sensed temperature and moisture, means for blowing air, an air conduit extending between the means for blowing air and the mill having an air valve therein, a mechanical linkage connected to the air valve for adjusting the position of the air valve to vary the quantity of air blown through said air conduit by the means for blowing air, an electric motor connected to the mechanical linkage for moving the mechanical linkage to vary the position of the air valve, means connected between the electric motor and the signal sensing and motor control unit for connecting the electric signal from the signal sensing and motor control unit to the electric motor, a water supply conduit terminating in nozzles within the air conduit down-stream of the air valve, a pressure regulator and a water volume control valve in said water conduit, and a mechanical linkage between the mechanical linkage for adjusting the air valve and the water volume control valve for varying the quantity of Water passed into the air conduit in accordance with the opposition of the air valve.

13. Structure for cooling granular material comprising a granular material cooling mill, a batch hopper for receiving a batch of granular material to be cooled for placement in the mill, means for sensing the temperature and moisture of the granular material in the batch hopper, a signal sensing and motor control unit connected to the moisture and temperature sensing means for developing an electric signal in accordance with the sensed temperature and moisture, means for blowing air, an air conduit extending between the means for blowing air and the mill having an air valve therein, a mechanical linkage connected to the air valve for adjusting the position of the air valve to vary the quantity of air blown through said air conduit by the means for blowing air, an electric motor connected to the mechanical linkage for moving the mechanical linkage to vary the position of the air valve, means connected between the electric motor and the signal sensing and motor control unit for connecting the electric signal from the signal sensing and motor control unit to the electric motor, a Water supply conduit terminating within the mill, means for supplying a batch of water through said water supply conduit in a cooling cycle, and means for determining the quantity of Water in the batch in accordance with the position of the air valve in the air conduit.

14. Apparatus for cooling granular material comprsiing a cooling mill, a batch hopper positioned over the cooling mill for receiving batches of granular material for cooling in the mill, moisture and temperature sensing means positioned in the batch hopper for determining the moisture and temperature of the granular material to be cooled, a signal sensing and motor control unit connected to the moisture and temperature sensing means for developing and electric signal in proportion thereto, an electric motor connected to the signal sensing and motor control unit for receiving the electric signal therefrom for movement in accordance therewith, a timer, mechanicial means extending between the timer and the electric motor for setting the timer in accordance with the movement of the electric motor, means for blowing air, an air condiut extending between he means for blowing air and the mill, air control means in the air conduit, a water conduit terminating in structure for feeding water into the mill including a pressure regulator, and a water volume valve in series therein and means for operating the air control means and the Water volume valve for a time determined by the timer during each cooling cycle.

References Cited UNITED STATES PATENTS 2,863,190 12/1958 Buhrer 22-89 2,821,375 1/1958 Andrews 2289 3,205,543 9/1965 Morris et al. 2289 3,230,589 1/1966 MCIlvaine 2289 J. SPENCER OVERHOLSER, Primary Examiner.

R. D. BALDWIN, Assistant Examiner. 

10. A METHOD OF COOLING GRANULAR MATERIAL COMPRISING SENSING THE TEMPERATURE AND MOISTURE CONTENT OF THE GRANULAR MATERIAL, BLOWING AIR THROUGH THE GRANULAR MATERIAL IN A QUANTITY IN ACCORDANCE WITH THE SENSED TEMPERATURE AND MOISTURE CONTENT OF THE GRANULAR MATERIAL, AND PROVIDING COOLING WATER IN THE GRANULAR MATERIAL IN RESPONSE TO AND IN ACCORDANCE WITH THE QUANTITY OF AIR BLOWN THERETHROUGH. 